JPH01204034A - Variable focal length camera and teleconverter device mounted on same or single-focus camera - Google Patents

Abstract

PURPOSE:To enable proper photography by providing a means which inhibits exposing operation on condition that a focal length selecting means selects a wide-angle side when the mounting of a teleconverter is detected. CONSTITUTION:When the teleconverter lens device 10 is mounted on a camera, the projection part 102 provided to the device 101 presses the movable contact 5a of a switch through an insulating elastic member 48 to make the contact. When a CPU 2 detects the on state of the switch, the wide-angle side is selected with a telephoto/wide-angle knob 7 and a switch 7b is turned on. At this time, the on signal of a shutter release switch 6 by the depression of a release button 47, i.e. release signal is not accepted and only when a switch 7a is turned on by selecting the telephoto side, the release signal is accepted to enable photography. Consequently, the periphery of a photographic image plane is prevented from being eclipsed to be an awkward photograph.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention relates to a variable focal length camera that can select a focal length on a telephoto side or a wide angle side, and a camera that is attached to the variable focal length camera. This invention relates to a teleconverter lens device. Note that the variable focal length camera referred to herein also includes a so-called zoom type camera in which the focal length can be selected stepwise from the telephoto side to the wide side.

(Background of the Invention) High-end cameras such as single-lens reflex cameras have traditionally been capable of changing the focal length, but it is desired that intermediate-level cameras also have this type of function.
For this reason, in recent years, two-point cameras have been commercialized that allow the focal length to be selected from either the telephoto side or the wide side. Furthermore, there is a teleconverter lens device as a variable focal length accessory that is attached to the front side of this type of camera. Since this device can easily change the focal length of a photographic lens fixed to an intermediate camera to a long focal length, demand for this device as an accessory for a camera is gradually increasing.

However, when using the two-point camera with the teleconverter lens device attached, if the focal length selection switch that selects the telephoto side or the wide side is set to the wide side, the incident light around the shooting screen will change. There were times when the image became vignetted, resulting in an unsightly photo with only the center area taken.

(Object of the Invention) An object of the present invention is to provide a variable focal length camera capable of taking appropriate photographs by fully utilizing the respective functions of a variable focal length camera and a pre-converter lens device attached to the camera. Another object of the present invention is to provide a teleconverter lens device that is attached to the variable focal length camera.

Another object of the present invention is to provide a teleconverter lens device that can accurately open and close a switch provided near a release operating member on the top surface of a camera.

(Features of the Invention) In order to achieve the above object, the present invention includes a detection means for detecting that a teleconverter lens device is attached, a focal length selection means for selecting a focal length on a telephoto side and a wide-angle side, and prohibiting means for prohibiting an exposure operation when a wide-angle side is selected by the focal length selecting means when the detecting means detects that the teleconverter lens device is attached; is provided with a protrusion that allows the detection means to detect the attachment of a teleconverter lens device attached to the variable focal length camera having the above configuration, so that when the teleconverter lens device is attached, the focal length is wide-angle. The feature is that the exposure operation is prohibited if the side is selected.

Moreover, when the present invention is attached to a variable focus camera,
A blocking means is provided to prevent the focal length selection means from selecting the wide-angle side, or when the focal length selection means is on the wide-angle side, this state is automatically canceled when the focal length selection means is attached to the variable focal length camera. The present invention is characterized in that it includes a release means, thereby making it impossible to select the wide-angle side by mounting the teleconverter lens device.

Furthermore, the present invention provides a switch means for detecting attachment of the teleconverter lens device near the release operation member on the top surface of the camera, and the switch means has an upper end disposed in the switch hole on the top surface of the camera and a movable switch means at the lower end. an insulating elastic member that is vertically movable and has a contact point;
．． This teleconverter lens device is attached to a camera and is configured with fixed contacts on a switch board facing each other with an interval of 2 mm, and the insulating elastic Push down the member 1.
By providing a protrusion with a length of 9 to 2.5 mm, the lower limit of the length of the protrusion is 1.9 mm to prevent contact failure of the switch means, and the upper limit to 2.5 mm to prevent insulation. It is characterized in that it prevents the elastic member from being unable to return.

(Embodiments of the Invention) Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is a schematic diagram showing an embodiment of the present invention. l
is a zone focus type bifocal camera, which includes a CPtJ2 that controls various operations of the camera, a known distance measuring circuit 3, and a stepwise drive controlled by the CPU 2 based on information from the distance measuring circuit 3. The photographic lens 4 is arranged near the release switch 6 which is turned on by the second stroke of the release button 47 on the top surface of the camera, has an upper end disposed in the switch hole on the top surface of the camera, and has a movable contact 5a at the lower end, and is movable up and down. A teleconverter lens device, which will be described later, is installed, which is composed of an insulating elastic member 48 and a fixed contact 5b on the switch board facing below the possible contact 5a with a 1.2 mm interval therebetween. It has a switch 5 for detection, a tele/wide selection knob 7 for selecting the focal length on the telephoto side or the wide side (selected by sliding toward the front or toward the back in the figure), and the like. Reference numeral 101 denotes a teleconverter lens device, which has a diameter of 1.9 mm to 2 mm on the lower surface of the hook member 104, which presses down the insulating elastic member 48 when attached to the camera l.
．． It has a protrusion 102 with a length of 5 mm, a teleconverter lens 103, etc.

When the teleconverter lens device 101 is attached to the camera 1, the protrusion 102 provided on the lower surface of the hook member 104 of the teleconverter lens device 101 presses the switch 5 via the insulating elastic member 48, turning it on. Make it.

When the CPU 2 detects that the switch 5 is turned on, the wide side is selected by the tele/wide selection knob 7 and the wide switch 7b is turned on, and when the wide switch 7b is turned on, the CPU 2 detects that the switch 5 is turned on. Release switch 6
The on signal, that is, the release signal, is not accepted, and the release signal is accepted only when the tele side is selected and the tele switch 7a is on, and photographing is possible.

With this configuration, when the teleconverter lens device 101 is attached, it is possible to reliably prevent the wide side from being selected and released, resulting in an unsightly photo with vignetting around the shooting screen. This is how it was done.

Next, we will begin to explain a specific example of the configuration of the camera 1 and the teleconverter lens device 101 shown in FIG. A description will be given of the drawbacks that may occur when photographing is performed in combination with an attachment device for changing the angle of view, such as a converter lens device, and what countermeasures are taken in this embodiment to this point.

First, the distance measurement method commonly used in this type of camera will be described. This type of camera generally uses the principle of triangulation as shown in Figure 14, and the light beam from the light source that emits infrared light for AF passes through the projection lens L1 to the subject a. A beam of light is projected upwards. The light reflected from the subject a is focused by the light receiving lens L2 arranged at a predetermined distance from the light projecting lens L1, and is imaged on the light receiving element S.
Distance information to the subject can be obtained from the imaging position above.
The photographing lens L3 is driven to a predetermined position according to the distance information, and focus adjustment is performed. By the way, the matching between this type of camera and the teleconverter lens device attached to it, for example, is not necessarily good, and if left as it is, the camera will be out of focus, making it difficult to get the full effect of installing the teleconverter lens device. For example, the relationship between the object distance Ri, the amount of lens drive, and the amount of defocus when focusing is performed by driving the entire photographing lens L3 is as shown in FIG. In FIG. 15, the object distance Ri is the object distance that accurately focuses on the lens drive amount di for the Zi-th zone, and the object distance iR1÷1 is the distance between the lens drive amount from the drive amount for the Zi-th zone to the Zi+1-th distance. This is the zone and zone switching object distance at which the drive amount for the zone is switched.

For the above camera, as shown in FIG. 16, a substantially afocal teleconverter lens device Lt is placed in front of the photographic lens L3, and the photographic lens L3 is driven to perform AP. The relationship between the lens drive amount di and the amount of defocus is as shown in FIG. 17, for example. Looking at Figure 17, when the focus adjustment operation is performed according to the lens drive amount determined by the original distance measurement result, a significant focus shift occurs near the zone switching point, and the performance exceeds the allowable focus limit. had deteriorated significantly.

In view of the above points, in this embodiment, the drive amount (extension amount) of the photographic lens L3 is corrected as follows to make it appropriate.

When focusing is performed by driving the entire photographing lens L3, the lens driving amount di with respect to the object distance Ri is expressed by the following approximate expression.

di~f” / (Ri −2f),...
...... ■In addition, in a zone focus type AF camera, the object distance for switching between zones also has an important meaning. The switching object distance iR1÷1 between the Zi-th zone and the Zi+1-th zone may be approximated by the object distance at which focus is achieved with respect to the lens drive amount (di+di+1)/2 in a lens capable of continuous focusing. here,
(di+di+1)/2 is the average of the lens drive amount of the Zi-th zone and the lens drive amount of the Zi+1-th zone.

Substituting (di+di◆1)/2 into rdiJ of the above equation 0 and solving Ri for iRi+1, we get iRi÷1 = 2f” / (di +di+1 )+
2f ...... ■On the other hand, when an afocal teleconverter lens Lt with magnification β is attached to the front side of the photographic lens L3, the lens drive amount di' for focusing at the object distance R1' is the same as the 0 type. is expressed by the following approximation formula, then di' given (f・β)''/ Ri' −2(f・β)
......■ In a zone focus type AF camera, the lens drive amount di' is determined in advance, and di
'=di. As a result, when we connect the right sides of the above equation 0 and equation (■) with an equal sign and solve for R1', we get Ri' = (Ri-2f) β'' + 2
(f・β) ・・・・・・■. Moreover, the switching object distance iRi+1' is the above-mentioned ■.

It is based on formulas such as ■ and ■. When the teleconverter lens device Lt is attached based on this formula, by changing the focusing point and switching point of the zone (see Figure 19), it is possible to obtain good performance with little focus deviation as shown in Figure 18. becomes possible. In addition,
Attachment lens systems are usually not strictly afocal systems, so in order to reduce the amount of focus deviation at the switching point in such cases, consider the refractive power arrangement of the attachment lens system and the photographing lens system, and It is desirable to determine the switching point through rigorous calculations. Furthermore, in order to reduce the amount of defocus at the switching point, it is preferable to determine the switching point by taking into consideration various aberrations such as spherical aberration and field curvature aberration when an attachment lens system is attached.

Next, a detailed configuration example of the camera 1 and the teleconverter lens device 101 shown in FIG. 1 will be explained. First, when the teleconverter lens device 101 is attached,
The configuration of a camera that changes the switching point of the photographic lens using the method described above and the operation of its main parts will be described.

FIG. 2 is a block diagram showing a specific example of the configuration of the camera according to the embodiment, and the same parts as in FIG. 1 are denoted by the same reference numerals. In the figure, 8 is a switch interface, 9
1 is a switch that is turned on by the first stroke of the release button 47, 10 to 20 are various mechanical switches inside the camera, 2
1 is a strobe control circuit, 22 is a flash discharge tube, and 23 is an A/
D converter, 24 is an analog multiplexer, 25 is a photometric circuit, 26 is a photometric sensor, 27 to 30 are adjustment volume resistors, 31.32 are current limiting resistors, 33.34
is LED, 35 is 1RED (infrared light emitting diode),
36 is a light receiving element (distance sensor), 37 is a film counter driver, 38 is a film counter, 39 is a motor driver, 40 is a motor, 41 is a plunger driver,
42 is a plunger, 43 is a photocoupler detection circuit, 4
4 is a light receiving element for photocoupler, 45 is L for photocoupler
ED, 46 is a pulse plate.

Next, the distance measuring operation and the AF control operation will be explained using the distance measuring circuit 3 whose specific example is shown in FIG. 3 and the timing chart of FIG. 4 according to the flowchart of No. 5N0).

The CPU 2 and distance measuring circuit 3 have four signal lines AFE.

Communication is performed with the SC through SDO and SDI, and when an H level is first input from the CPU 2 through the signal line AFE, the AF control logic 51 in the distance measuring circuit 3 starts a distance measuring operation. Note that while the L level is being input through the signal line AFE, the AP control logic 51 is in a reset state, setting each signal processing system to its initial state.

Next, a serial synchronous clock is inputted from the CPU 2 through the signal line SCK, and at the same time, in synchronization with the falling edge of the serial synchronous clock, the first status data (indicated as 4-bit data in FIG. 4) is inputted through the signal line SDO. Normally, an H level is input through the signal line SDO, and the first two bits of the status data transferred thereafter are L level and represent a start bit, and the remaining two bits represent the status contents. the signal line SC and the signal line S
When a signal as shown in Fig. 4 is input through DO, A
The P control logic 51 generates a 1RQN signal by dividing the frequency of the serial synchronization clock by 1, and sends the iRON signal to the operational amplifier 52. Transistor 53° Resistor 54.5
Output to 1RED driver consisting of 5. As a result, 1RED35 performs AC drive at a constant cycle (iRON
1RED35 lights up when the signal is H level, i RON
When the signal is at L level, 1RED35 is off). When all 4-bit status data have been input, the output 5PLI is set to H level in synchronization with the lighting state of the 1RED 35 in order to set the status of the rising integral.

Here, the infrared light emitted from the 1RED 35 is reflected by the object surface and enters the light receiving element 36, where it is converted into signal currents Ia and Ib. Based on the principle of triangulation, the position of the incident light on the light receiving element 36 differs depending on the distance from the camera body to the subject, and the current distribution ratio of Ia and Ib changes depending on the position of the incident light.
The value of Ib)/(Ia+Ib) corresponds one-to-one to the distance from the camera body to the subject. The light receiving element 36
The signal current Ia generated by the operational amplifier 56. resistance 57
After being converted into a signal voltage Va by a current-to-voltage converter consisting of a current-to-voltage converter, and further having a DC component cut by a capacitor 58, a subtraction circuit 59. The signal is input to an adding circuit 60. Similarly, the signal current Ib is converted to a signal voltage vb by a current-voltage converter composed of an operational amplifier 61 and a resistor 62, and after the DC component is cut by a capacitor 63, a subtraction circuit 59. The signal is input to an adding circuit 60. In the subtraction circuit 59, (Va-vb
) is calculated, and this output is passed through an analog switch 64 to a resistor 65 . The signal is input to an integrator consisting of a 66° operational amplifier and a capacitor 67.

On the other hand, the adder circuit 60 calculates the value (Va+Vb), and this output is input to the integrator through the analog switch 68. Since the analog switch 64 is turned on at the H level of the output 5PLI, the output of the subtraction circuit 59 is integrated in synchronization with the H level signal of the output 5PLI, and as shown in FIG. Output 1NTO
UT rises above the reference level KVC. At this time CPU2
measures this integration time with an internal timer 1 (not shown), and when a predetermined time t1 is reached, the signal line SDO is connected again.
The following status data will be transferred through: The status data at this time instructs the interval mode setting, so in this case the AF control logic 5
1 fixes both outputs 5PLI and 5PL2 to L level to form an integration stop time (interval period).

When the above state continues for a predetermined time t2, the CPU 2 transfers the next 4-bit status data through the signal line SDO, that is, data for setting the status of the falling integral. As a result, the AF control logic 51 sets the output 5PL2 to H level in synchronization with the extinguished state of the 1RED 35 (see FIG. 4). Therefore,
The output of the adder circuit 60 is integrated by an integrator, and the output 5PL2 has a phase of 1 with respect to the output 5PLI.
Since the difference is 80", the integrator output 1NTOUT falls. Integration in this direction progresses and the integrator output 1NTQLI
When T becomes lower than the reference level KVC, comparator 6
9's output AFCOMP becomes H level, and this signal becomes A
It is output to the CPU 2 side through the P control logic 51 and the signal line SDI. The CPU 2 stops the internal timer 1, which was started at the same time as the start of the downward integration, and calculates the time t3.
is stored in an internal register Ml (not shown), and at the same time, the next status data (data instructing the end of integration) is transferred to the AF control logic 51 via the signal line SDO. At the same time as receiving this status data, the AF control logic 51 stops outputting the iRQN signal, stops driving 1RE035, and further outputs 5pL.
1 and 5PL2 are both set to L level, and the integration operation is completed. Here, the value of t3 is t3= (I a - I b) / (I a + Ib)
・tt, so if tl is the default time, the value of t3 is proportional to (Ia-Ib)/(Ia+Ib), so
The position of incidence on the light receiving element 36 can be determined from the value of t3.

Subsequently, the CPU 2 sets the signal line AFE to L level, ends the control of the distance measuring circuit 3, and starts the data conversion operation of the falling integral time stored in the internal register M1. In FIG. 2, when the teleconverter lens device 101 is attached, the switch 5 is turned on, and when it is not attached, it is turned off.The CPU 2 takes in the state of the switch via the switch interface 8, and The distance measurement results are shifted depending on the situation. In the flow of FIG. 5(b), the lens is at the switching point. The object distance information is stored in an internal memory (not shown) as corresponding downward integration time data x1 to xn, y1 to yn. Here, according to the known principle of triangulation, the amount of lens driving is determined by the light receiving element 35.
From the point where it is almost proportional to the amount of movement above, x1 ~ x
n, yt to yn are values that are approximately equally spaced (discrepancies occur as the distance approaches), and the final ranging information is calculated by comparing this switching data with the value of the internal register Ml. It is something. In FIG. 5(b), initially the output AFDATA and the data comparison counter i have a value of "1".
" is assigned, and if the teleconverter lens device 101 is subsequently attached, "y" is assigned to internal register a.
If it is not attached, substitute "xl". Here, the value of the internal register M1 and the value of the internal register a are compared, and if M1≦a, the data comparison operation is ended and the value of the output AFDATA at that time is stored in the internal register M2 as lens drive amount information. In addition, when Ml > a, the value of output AFDATA and data comparison counter i is
+1” and set “xl” or “y2” to internal register a.
rMIJ and raJ are compared again, and the comparison operation is repeated until M1≦a (see Figure 6).
.

In this way, by sequentially comparing the value of the falling integration time t3, which means the incident position of the signal reflected light to the light receiving element 36, with the time data corresponding to the zone switching distance, the final lens drive amount information can be calculated. can.

Next, it is determined again whether the teleconverter lens device 101 is attached, and if it is determined that it is not attached,
If the release switch 6 is turned on by the second stroke of the release button 47, the shutter opening operation starts immediately, but if it is determined that the camera is attached (switch 5 is turned on), then It detects whether the focal length of the photographing lens 4 is on the telephoto side or the wide side, and if it is on the telephoto side (when the telephoto switch 7a is on), the shutter is opened immediately by turning on the release switch 6. When the shutter operation is started and it is on the wide side (when the wide switch 7b is on), the shutter operation does not shift to the opening operation, that is, the shooting operation, even if the release switch 6 is on, and the release button 47 is pressed. After the switch 9, which is turned on during the first stroke, is turned off, it returns to the initial state.

Next, the configuration of the teleconverter lens device 101 will be explained.

FIG. 7 is a perspective view of the teleconverter lens device 101, FIG. 8 is a rear perspective view showing the device 101 attached to the camera 1, and FIG. 9 and FIG.
11 is a sectional view taken along the line AA' shown in FIG. 8, FIG. 12 is a top view shown in FIG. 8, and FIG. 13 is a top view shown in FIG. 8. In FIGS. 7 to 13, the same parts as in FIG. 1 are designated by the same reference numerals.

The teleconverter lens device 101 includes a teleconverter footer 104, a teleconverter cover 105, and a teleconverter base plate 106.
, a spacer 107, a teleconverter lens 103, a finder lens 108a, 1osb, a mounting base 109, a tripod screw 110, mounting screws 1lla and 1llb, and spring pins 112a and 112b.

The teleconverter hook 104 is rotatably supported on the teleconverter cover 105 by a spring pin 112b. In addition, a camera 1 is provided on the bottom surface of the teleconverter hook 104.
A protrusion 102 is provided which is configured to press the switch 5 (see FIG. 1.2) provided on the side via the insulating elastic member 48. The teleconverter lens 1
03 is held on the teleconverter main plate 106, and spacer 107
The air gap is regulated by the front lens 103a by the lens receiving part 105a of the teleconverter cover 105 and the spacer 107, and the rear lens 103b by the lens receiving part 106a of the teleconverter main plate 106 and the spacer 107. It is positioned in the front-back direction. Further, the finder lenses 108a and 108b are attached to the lens receivers 106c and 106d of the teleconverter base plate 106, and are fixed to the teleconverter cover 105 with mounting screws 1llb, thereby constituting an auxiliary lens optical system as a whole. The mounting base 109 is a spring bin 112a.
The device 101 is rotatably supported by the teleconverter cover 105, and a tripod screw 110 for attaching the device 101 to the camera 1 body is attached.

Here, the protruding portion 102 is arranged so that the device 101 is connected to the camera 1.
When attached to the main body, r 19 mmJ in front from the film surface of camera 1, and r 14 in the height direction from the shooting optical axis.
．． 2mmJ, also r30mmJ to the left in Figure 13
It is located at the position, its outer diameter is "φ1.7", and the height (length)
is r2.2mmJ.

By the way, although the protrusion 102 can be disposed on the mounting base 109 or the teleconverter base plate 106, it is disposed on the teleconverter hook 104 for the following reason.

1) When the protrusion 102 is arranged on the mounting base 109,
While the photographer attaches the device 101 to the camera 1 with the tripod screw 110, the teleconverter lens 103, the teleconverter hook 104, etc. escape to the bottom of the camera, that is, the teleconverter cover 105 and the teleconverter cover 105 center around the spring bin 112a in FIG. Rotate the teleconverter hook 104 counterclockwise and retract it to the bottom of the camera.
When attempting to take a picture (without using the device 101),
Since the switch 5 remains on, the device 1
The CPU 2 determines that the device 101 is attached, so even if the photographer tries to take a picture without the device 101, AF correction will be performed, resulting in an out-of-focus photo. In order to prevent this, the photographer must also remove the mounting base 109, resulting in a lack of maneuverability.

2) If the protruding portion 102 is provided on the teleconverter base plate 106, the problem like 1) above will be eliminated, but the switch 5 will need to be provided on the front side of the camera, which is not preferable since it will spoil the appearance. It's not a thing. Furthermore, as a protrusion that will be attached to the teleconverter base plate 106, the mounting tolerance of the mounting base 109 and the tripod screw 110,
The hinge position tolerance between the mounting base 109 and the teleconverter cover 105, the tolerance between the hinge position (spring bin 112a position) and the mounting position of the teleconverter base plate 106, and the height tolerance between the mounting position of the teleconverter base plate 106 and the tip of the protrusion. In addition to the dimensional tolerance, the positional tolerance of the teleconverter hook 104 and the teleconverter cover 105 is affected by their height,
When installing the teleconverter lens device 101, it is difficult to ensure that the switch 5 is turned on.

Further, the position of the protruding portion 102 is r19 mmJ forward from the film surface, which is approximately 1/2 of the distance from the rotation center of the teleconverter hook 104 to the hook portion 104a (see Fig. 9.10). , Telephone hook 1
04 to turn on the switch 5 with reliable pressure based on the lever principle, and thus stable switch input can be achieved. Also, in FIG. 13, the protruding portion 102 located at a position r30 mmJ to the left from the optical axis direction is arranged on an extension line of the hook portion 104a of the teleconverter hook 104 that is substantially parallel to the optical axis. It enables reliable switching based on the principle of
Placing it near the release switch 6 (release button 47) in the figure has the advantage that, for example, the flexible board on which the fixed contact 5b is provided can be shared with the release switch 6. It is easy to do and can prevent cost increases.

Furthermore, regarding the protrusion 102, the front cover 4 of the camera l
9a and the rear cover 49b are bent and deformed due to their assembly, and even if the teleconverter hook 104 is elastically deformed due to the pressure of the protrusion 102 against the switch 5, the switch r2.
It is 2mm J. This is the movable contact 5 of switch 5
A is a fixed contact 5b (
This is the height at which it is possible to push further by r1 mmJ after contacting (see Fig. 10). In this embodiment, the protrusion 102
The height is set at 2.2 mm, but taking into consideration the height that can be pushed further (0.7 to 1°3 mmJ), approximately 1.9 to 2.5 mmJ is appropriate.

To attach the teleconverter lens device 101 as described above to the camera 1, first screw the tripod screw 110 attached to the mount 109 into the tripod screw hole provided in the camera 1. Thereafter, the teleconverter cover 105 is rotated clockwise in FIG. 9.10 so as to come into contact with the front cover 49a of the camera 1, using the spring bin 112a as a rotation axis.

FIG. 10 shows the state in which the above mounting operations have been performed.

Next, the teleconverter hook portion 104 is rotated clockwise in FIG.
04b respectively to the engaging portions of the rear cover 49b of the camera 1, and the mounting is completed.

The AF camera of this embodiment has a bifocal function, and when the teleconverter lens device 101 is attached, the photographing lens 4 of the camera body is extended to the telephoto side as described above, that is, as shown in FIG. It is electrically constructed so that it can take a picture for the first time when it is extended to the position indicated by the dashed line, but for further safety, this can also be achieved mechanically.

That is, the hook portion 104a of the teleconverter hook 104
As can be seen from Fig. 12, the rear cover 4 of the camera 1 is closed only when the tele/wide selection knob 7 is located on the tele side.
9b (see FIG. 9.10), and the hook portion 10
4a is provided with an inclined surface, which has one of the roles of restricting the tele/wide selection knob 7 from inadvertently moving toward the wide side. In addition, the hook portion 1
Another role of the inclined surface 04a is that when the tele/wide selection knob 7 is located on the wide side and the device 101 is forcibly attached, the tele/wide selection knob 7 7 to the inclined surface and move it to the telephoto side. When the above operations are completed, the teleconverter lens device 101 is arranged between the tripod screw 110 and the tripod screw hole of the camera body in the left-right direction, and on the teleconverter base plate 106 in the front-rear direction with respect to the camera 1. A contact protrusion (not shown) attached to the front cover 4 of the camera 1
The respective positions are determined by coming into contact with 9a.

In this state, the protruding portion 102 provided on the teleconverter hook 1O4 makes contact with the fixed contact 5b and movable contact 5a of the flexible board located at a location configured to cover the top surface of the finder block (not shown). That is, the movable contact 5a is pressed downward as shown in FIG. 9 to ensure that the switch 5 is turned on. This allows the CPU 2 in the camera 1 to know that the teleconverter lens 101 is attached.

(Correspondence between the invention and the embodiment) In this embodiment, the tele/wide selection knob 7, the tele switch 7a, and the wide switch 7b serve as the focal length selection means of the present invention, the CPU 2 serves as the control means, and the switch 5 serves as the teleconverter lens. The protrusion 102 corresponds to a switch means for detecting attachment of the device 101, and the protrusion 102 corresponds to a protrusion for pressing the switch means to change the state.

(Modification) In this embodiment, the CPU 2 detects that the teleconverter lens device 101 is attached, and controls the extension of the photographing lens 4 by correcting the distance measurement data to the subject. However, the present invention is not limited to this, and the device may be configured to detect that the device is attached, change the mechanical means for extending the photographic lens, and correct the amount of extension. Furthermore, it is also possible to correct the distance measurement data by arranging a plurality of AF light receiving element arrays with different pitch intervals and selecting and using one of them when the device 101 is mounted. Furthermore, the hook part 1 of the teleconverter hook 104
The inclined surface provided at 04a has a function of forcibly moving the tele/wide selection knob 7 to the tele side when the device 101 is attached when the tele/wide selection knob 7 is on the wide side. However, this tele/wide selection knob 7
If the switch is also used as the main switch, it is possible to force it to be placed on the telephoto side no matter what other positions (off position, macro shooting position, etc.) it is in. It is.

In addition, although this embodiment describes the case where it is applied to a bifocal camera, it is not limited to this, and can also be applied to a multifocal camera. This refers to the range in which vignetting does not occur when the converter lens device 101 is attached.

(Effects of the Invention) As explained above, according to the present invention, when the teleconverter lens device is attached, the exposure operation is prohibited if the wide-angle side is selected as the focal length. It becomes possible to take appropriate photographs that fully utilize the functions of the variable focal length camera and the pre-converter lens device attached to the camera.

Further, according to the present invention, since selection of the wide-angle side is made impossible by mounting the teleconverter lens device, prohibition of exposure operation is no longer activated, and the camera can always perform exposure operation.

Furthermore, according to the present invention, the lower limit of the length of the protrusion is set to 1.9 m.
By setting the upper limit to 2.5 mm, it is possible to prevent poor contact of the switch means, and by setting the upper limit to 2.5 mm, it is possible to prevent the insulating elastic member from being unable to return to its original position. Able to perform movements accurately.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a specific example of the configuration of the camera shown in FIG. 1,
3 is a block diagram showing a configuration example of the distance measuring circuit shown in FIG. 2, FIG. 4 is a time chart during operation of the distance measuring circuit shown in FIG. 3, and FIG. A flowchart showing the operation of the main parts of the illustrated camera, FIG. 6 is a diagram showing the relationship between the integration time and the lens extension amount, and FIG. 7 is a perspective view showing a specific example of the configuration of the teleconverter lens device shown in FIG. 1. 8 is a rear perspective view showing the teleconverter lens device shown in FIG. 7 attached to the camera configured in FIG. 2, and FIGS. 9 and 10 are cross-sectional views taken along line B-B' shown in FIG. 8. , Figure 11 is the 8th
Fig. 12 is a top view shown in Fig. 8, Fig. 13 is a top view shown in Fig. 8, and Fig. 14 explains the distance measurement method of a general zone focus type AF camera. figure,
FIG. 15 is a diagram illustrating the lens extension control, FIG. 16 is a diagram showing a case where a teleconverter lens device is attached to a conventional camera of this type, and FIG. 17 is a diagram showing the lens in the case shown in FIG. 16. FIG. 18 is a diagram illustrating the lens extension result by the AF correction method employed in this embodiment, and FIG. 19 is a diagram illustrating the lens extension position at that time. 1...Camera, 2---CPU, 5...
...Switch, 6...Release switch,
7... Tele/wide selection knob, 7a...
...Tele switch, 7b...Wide switch,
47... Release button, 48... Insulating elastic material, 101... Teleconverter lens device,
102... Protruding portion, 103... Teleconverter lens, 104... Teleconverter hook. Patent applicant Canon Co., Ltd.

Claims (5)

[Claims] (1) A detection means for detecting that a teleconverter lens device is attached, a focal length selection means for selecting a focal length on the telephoto side and a wide-angle side, and the teleconverter lens device is attached by the detection means. 1. A variable focal length camera comprising: a prohibiting means for prohibiting an exposure operation when a wide-angle side is selected by the focal length selecting means when the focal length is detected. (2) A detection means for detecting that a teleconverter lens device is attached, a focal length selection means for selecting a focal length on the telephoto side and a wide-angle side, and the teleconverter lens device is attached by the detection means. A teleconverter lens device mounted on a variable focal length camera, comprising: a prohibition means for prohibiting an exposure operation when a wide-angle side is selected by the focal length selection means when the focal length selection means is detected. . A teleconverter lens device, comprising: a protrusion that allows the detection means to detect attachment of the teleconverter lens device. (3) A detection means for detecting that the teleconverter lens device is attached, a focal length selection means for selecting the focal length on the telephoto side and the wide-angle side, and the teleconverter lens device is attached by the detection means. A teleconverter lens device mounted on a variable focal length camera, comprising: a prohibition means for prohibiting an exposure operation when a wide-angle side is selected by the focal length selection means when the focal length selection means is detected. . A teleconverter lens device, characterized in that the teleconverter lens device is equipped with a blocking device that prevents the focal length selecting device from selecting a wide-angle side when the teleconverter lens device is attached to the variable focus camera. (4) A detection means for detecting that the teleconverter lens device is attached, a focal length selection means for selecting the focal length on the telephoto side and the wide-angle side, and the teleconverter lens device is attached by the detection means. A teleconverter lens device mounted on a variable focal length camera, comprising: a prohibition means for prohibiting an exposure operation when a wide-angle side is selected by the focal length selection means when the focal length selection means is detected. 2. A teleconverter lens device comprising: a canceling device that automatically cancels this state when the focal length selecting device is on the wide-angle side when the variable focal length camera is attached to the variable focal length camera. (5) A switch means for detecting attachment of the teleconverter lens device is provided near the release operation member on the top surface of the camera, and the switch means has an upper end disposed in the switch hole on the top surface of the camera and a movable contact at the lower end. A telephoto lens attached to a variable focal length camera or a single focus camera, which is composed of an insulating elastic member that is movable up and down, and a fixed contact on a switch board facing below the movable contact with an interval of 1.2 mm. 1. A teleconverter, which is a converter lens device, characterized in that a protrusion with a length of 1.9 to 2.5 mm is provided on the lower surface of a hook member that is latched to the upper surface of the camera to push down the insulating elastic member. lens device.